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Unit converter

Convert between metric, imperial and US units in one place. Pick a category, enter a value and see the result, plus the same value in every other unit.

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How to use the unit converter

  1. Choose a category: length, weight, temperature, volume, area or speed.
  2. Enter a value and choose the units to convert from and to. Use the swap button to reverse the conversion.

Under the main result you will see your value converted into every other unit in that category. That is handy when you are not sure which unit you need.

Common conversion factors

FromToMultiply by
KilometresMiles0.621371
MilesKilometres1.609344
KilogramsPounds2.204623
PoundsKilograms0.453592
CentimetresInches0.393701
LitresUS gallons0.264172
Square metresSquare feet10.7639
km/hmph0.621371

Temperature formulas

Temperature cannot be converted with a single multiplier because the scales start at different zero points:

°F = °C × 9/5 + 32  ·  °C = (°F − 32) × 5/9  ·  K = °C + 273.15

Example: 25 °C × 9/5 + 32 = 77 °F. A quick mental estimate is "double it and add 30", which gives 80 °F.

Worked examples

  • A 10 km run is 10 × 0.621371 = 6.21 miles.
  • A 23 kg airline baggage limit is 23 × 2.204623 = 50.7 lb.
  • A 12 stone 4 lb person weighs (12 × 14 + 4) × 0.453592 = 78.0 kg.

UK vs US units

Be careful with gallons and pints: a UK (imperial) gallon is 4.546 litres, while a US gallon is 3.785 litres. Fuel economy in miles per gallon (mpg) therefore differs between UK and US figures for the same car. Cups and tablespoons in this converter use US measures.

Frequently asked questions

How many miles is 1 km?
1 kilometre is 0.621371 miles. 1 mile is exactly 1.609344 kilometres.
How do I convert kg to stone and pounds?
Divide the kilograms by 6.35029 to get stone. Multiply the decimal part by 14 to get the pounds. For example, 80 kg = 12.6 stone = 12 st 8 lb.
What is 180 °C in Fahrenheit?
180 × 9/5 + 32 = 356 °F. That is the usual oven temperature written as 350–356 °F in recipes.
Are the conversion factors exact?
Many are exact by definition: 1 inch = 2.54 cm, 1 lb = 0.45359237 kg, 1 mile = 1,609.344 m. Results are rounded to six decimal places for display.

Last reviewed: November 13, 2026

Results are estimates for general information only and are not financial, tax, medical or legal advice. Check important figures with a qualified professional.